I would be very interested in what yours looks like, does your brick glow, do you have gaps around it? How far do you end up opening the gas valve?
I would think gas pressure would push the needle valve up. I do notice a decrease in gas if I push the knob down, but it come back when I release. Or is there a floating seat that is picking up and the spring would hold it in place?Push down the Gas regulator...
3 of my Accuctaft regulators have the same vertigal play
I installed a coil spring underneat which took care of the play